Combinatorial pharmacogenomics and improved patient outcomes in depression: Treatment by primary care physicians or psychiatrists

Abstract Failed medication trials are common in the treatment of major depressive disorder (MDD); however, the use of combinatorial pharmacogenomics to guide medication selection has been previously associated with improved outcomes in the psychiatric care setting. The utility of combinatorial pharmacogenomics in patients with MDD in primary care and psychiatric care settings was evaluated here. Patients enrolled in a naturalistic, open-label, prospective study [Individualized Medicine: Pharmacogenetics Assessment and Clinical Treatment (IMPACT)] with MDD were evaluated (N = 1871). Pharmacogenomic testing was performed for all patients and medications were categorized based on gene-drug interactions. Beck's Depression Inventory (BDI) was evaluated at baseline and follow-up (weeks 8–12). Symptom improvement (percent decrease in BDI), response (≥50% decrease in BDI), and remission (BDI≤10) at follow-up were evaluated according to provider type and whether medications were genetically congruent (little/no gene-drug interactions). There was a 27.9% reduction in depression symptoms at follow-up, as well as response and remission rates of 25.7% and 15.2%, respectively. Outcomes were significantly better among patients treated by primary care providers versus psychiatrists (symptom improvement 31.7% versus 24.9%, p